1. Field of the Invention
The present invention relates to seals for use in a mechanical press and more particularly to seals which are selectively engageable and have low maintenance requirements. Specifically, this invention relates to the use of selectively engageable seals to control lubricant leakage in a mechanical press.
2. Description of the Related Art
Mechanical presses of the type performing stamping and drawing operations employ a conventional construction that includes a frame structure having a crown and a bed and which supports a slide in a manner enabling reciprocating movement toward and away from the bed. Conventional presses additionally include a gib. A gib is a mechanism in stamping or drawing presses which works to contain the lateral motion of a reciprocating slide in a direction substantially normal to the direction of the slide""s reciprocating movement.
Press machines are widely used for a variety of workpiece operations and employ a large selection of die sets, with the press machine varying considerably in size and available tonnage depending on its intended use.
State of the art mechanical presses provide lubrication between the gib and the slide to facilitate and contain slide movement. The lubrication contained between the slide and the gib has a tendency to be pushed out and may leak onto the bed of a press. Factors such as press speed, tipping moment, applied load, and wear contribute to the likelihood of lubrication leaks.
Lubrication from portions of a mechanical press contained in the crown (among other places) may leak into the area between the slide and the gib. Additional lubricant entering the area between the gib and the slide exacerbates the problem of lubrication exiting the area between the gib and the slide and possibly finding its way onto the bed of the mechanical press. Leaking lubricant from other portions of a mechanical press (e.g. the crown) may also leak into other portions of the press (e.g. the bed) and cause problems.
Leaking lubricant may pass from the gib, down the slide and onto the parts being stamped on the press. In some production environments, oil leaks will cause scrapping of stamped product which leads to increased cost and production time.
Different sealing arrangements have been utilized in an effort to prevent lubricant from contacting stock material in a mechanical press. Current state of the art seals include seals which have flexible wiper portions which experience mechanical wear. This mechanical wear causes these seals to fail and leak. Frequent removal and replacement of these seals necessitate that the press be off-line and disassembled to obtain service access to the gib assembly.
What is needed in the art is a seal mechanism for sealing the area between the gib and the slide of a mechanical press in which the seal mechanism is adjustable controlled, and does not require frequent maintenance.
What is additionally needed in the art is a seal mechanism for a mechanical press which is selectively actuatable depending upon the operating condition of the mechanical press.
The present invention is directed to improve upon the aforementioned mechanical press sealing mechanisms, wherein it is desired to prevent lubricant from contacting stock material without experiencing frequent down time for seal replacement. The present invention also improves upon the current state of the art sealing mechanisms for a mechanical press by providing a selectively actuatable sealing arrangement which is responsive to press operational condition.
The present invention provides a seal mechanism for a mechanical press which includes seal surfaces which can be selectively engaged and are made from a highly wear resistant, low friction material.
The invention, in one form thereof, comprises a press which includes a sealing mechanism. The press includes a bed which is connected to a pair of uprights. The uprights are further connected to a crown. In this form of the current invention, the press includes a gib attached to the press and a selectively inflatable seal. The selectively inflatable seal is connected to the press and can be disposed between the slide and the uprights, the slide and the crown, or the slide and the gib.
The invention, in another form thereof, comprises a press which includes a selectively inflatable seal. In this form, an inflator selectively inflates the linear seal. A controller, which selectively actuates the inflator may be employed. The controller receives values corresponding to press operational condition and signals the inflator to inflate the linear seals when one of the values exceeds a predetermined measure. The values received by the controller include, for example, a measure of press tipping moment, a measure of applied load, a measure of press speed and/or a measure of sensed oil leaks.
The invention, in another form thereof, comprises a press including a press frame. A slide is mounted within the frame for reciprocation relative to the frame. A gib is connected to the frame and a plurality of linear seals are located between the gib and the slide and selectively form a cavity therebetween. In one form of the current invention, the linear seals are lengthwise substantially parallel to the direction in which the slide reciprocates.
The invention, in another form thereof, includes a plurality of wear plates which have wear plate contact surfaces and which maintain a position between the slide and the gib. The wear plates are connected either to the slide or the gib and are configured such that the wear plate contact surfaces are opposite and substantially parallel to gib contact surfaces or slide contact surfaces, respectively. A plurality of linear seals selectively form a cavity with the gib and the slide. The plurality of wear plates are located within the cavity. In one form of the current invention, the wear plates have a surface finish that is approximately within the range of 16 to 32 microfinish.
The invention, in another form thereof, includes a plurality of linear strips of wear material which are affixed to a plurality of linear seals such that when the linear seals are actuated, the linear strips of wear material contact the slide and form the seal contact surface. The strips of wear material are formed from a highly wear resistant, low friction material which can be, for example, TEFLON or TURCITE.
The invention, in another form thereof, comprises a press which includes a press frame. A slide is mounted within the frame for reciprocation relative to the frame and a gib is connected to the frame. A plurality of linear seals selectively form a cavity with the gib and the slide. A collection means, for example, a collection tray, collects lubricant from the cavity.
The invention, in another form thereof, comprises a press including a plurality of inflatable linear seals which selectively form a cavity with the slide and the gib of the press. In this form, an inflator selectively inflates the linear seals. A controller, which selectively actuates the inflator may be employed. In one form of the current invention, the controller receives values corresponding to press operational conditions and signals the inflator to inflate the linear seals when one of the values exceeds a predetermined measure. The values received by the controller include, for example, a measure of press tipping moment, a measure of applied load, a measure of press speed and/or a measure of sensed oil leaks.
The invention, in another form thereof, comprises a press which includes a press frame. A slide is mounted within the press frame for reciprocation relative thereto. A gib is connected to the frame and includes a plurality of linear grooves. A plurality of linear seals occupy the grooves in the gib and selectively form a cavity with the gib and the slide. The plurality of linear seals comprise a plurality of linear strips of steel which have sealing surfaces. A plurality of linear strips of wear material are affixed to the sealing surfaces of the plurality of linear strips of steel. In this form, the linear grooves include pressure chambers which selectively apply a pressure to the linear seals causing the linear seals to form a cavity with the gib and the slide.
The invention, in another form thereof, comprises a press which includes a press frame. A slide is mounted within the press frame for reciprocation relative thereto. A gib is connected to the frame and a linear seal surrounds the slide and selectively forms a seal between the slide and the gib.
The invention, in another form thereof, comprises a press. The press includes a frame and a slide mounted within the frame for reciprocation relative thereto. The slide has four corners each of which has a front-to-rear and a left-to-right touch surface. A plurality of wear plates having wear plate contact surfaces are affixed to each of the touch surfaces of the slide. In this form, the invention includes a plurality of seal contact blocks which correspond in number to the wear plates. One of said plurality of seal contact blocks extends outwardly from each wear plate. A gib is affixed to the frame and has a plurality of gib contact surfaces corresponding in number to the wear plates. The gib contact surfaces are opposite and substantially parallel to the wear plate contact surfaces. A plurality of inflatable linear seals are connected to the gib. One of the plurality of linear seals selectively contacts each of the contact blocks. In this way, the linear inflatable seals form four sealed cavities one at each of the four corners of the slide. Each of the sealed cavities vertically encloses the front-to-rear and the left-to-right touch surface at each corner of the slide. A linear strip of wear material is affixed to each of the linear seals such that it forms the surface of the linear seal which contacts the slide. A collection tray is configured for collecting lubricant from each of the sealed cavities.
An advantage of the present invention is the ability to prevent lubricant from contacting stock material without utilizing a sealing arrangement which requires frequent maintenance.
Another advantage of the present invention is that the seals of the present invention may be selectively engaged depending upon the operational condition of the mechanical press.